1. Field of the Invention
This invention concerns a liquid crystal device for use in liquid crystal display devices, liquid crystal light valves, etc.
2. Description of the Prior Art
Technical attention has been attracted in recent years to liquid crystal device using ferroelectric liquid crystals in the field where high speed responsivity is required.
Heretofore, two types of systems have mainly been studied for the display by the use of ferroelectric liquid crystals, that is, a system of birefringent mode display in which a liquid crystal cell is placed between two polarizing plates and optical axes for the liquid crystal molecules are varied by the voltage application for the display and a guest-host mode in which a dichromic pigment is added to the liquid crystal and color-switching is conducted by using a sheet of polarizing plate.
Although the birefringent mode display system has a feature that a high contrast can be obtained by the polarizing plates, the display quality is poor, since there occurs a remarkable coloration due to interferring colors unless the cell gap is restricted to less than 2 .mu.m and, in addition, the hue of the interferring color varies by the scattering of cell gaps making it difficult to obtain uniform display. If the cell gap is reduced to less than 2 .mu.m, although the coloration is less prominent, there are a lot of technical problems in the upon manufacturing a large area panel with such a thin cell gap.
While on the other hand, in the guest-host mode display system, scattering of the cell gap provides no remarkable direct effects on the optical properties as in the birefringent mode cell and the liquid display device can be manufactured with cells having the same extent of gap as in the commercially available TN mode display devices. However, it is difficult to obtain a high contrast and, particularly, a great amount of pigment has to be added for black and white display to bring about problems in the brightness of the display and the life and reliability of the device.